Science Buddies: "Ask an Expert"

I'm thinking about doing this year's science fair on Ethanol. It just seems like a good, recent idea. I have two ideas, and I need help on both of them.
If you can, could you please tell me which acids I would need to isolate the cellulose/starch and/or what procedures I would need to do as the pretreatment. I would like to use acids to isolate the cellulose instead of enzymes because it seems a bit easier to obtain. I've read that I will need to add a base to the material after the acid to neutralize it. Is this correct? If so, how much base? and what kind?
I've also read that certain inhibitors are created after the acid and base have been created, and I would have to boil the material to let it evaporate before the fermenting. Is this correct? Will I need to get rid of any other chemicals in the solution?

And then for the fermenting, do I just leave the material in a closed container? I've read that adding yeast to the material helps it ferment faster. Is this true?

IF you have ANY knowledge on any of these, could you please help. It would be greatly appreciated

So for the two possible tests, I'm thinking of either:
-Testing which vegetable/fruit/plant would produce the most ethanol. I would compare prices and availability also
-Testing which sugar creates more ethanol. For this one, I will either get actually sugars like glucose, fructore, sucrose, etc ORRR I will test different polysaccarrids such as cellulose and starch.

Again, any help would be greatly appreciated PLEASE HELPP

Hi,

This is a great idea for a project. However, before you continue, please check with your teacher and make sure you can get approval for doing a project on ethanol, If not, then you will need to select a different topic. Here is information on the Scientific Review Committee from the Science Buddies website; you definitely need preapproval for this project since ethanol is considered a hazardous substance.

https://www.sciencebuddies.org/science- ... _src.shtml

In the meantime, please do some additional background reading to learn more about your topic. It sounds like you are interested in doing a biofuels project and this will be very challenging. The acid hydrolysis you have read about involves using 5-6 M sulfuric acid to break down the lignin in the plant to release and hydrolyze the cellulose in the plant to glucose. Sometimes a pretreatment step is used to help break down the lignin structure of the plant. The acid is neutralized using sodium hydroxide. The high salt can be removed using an ion exchange resin to deionize the sample. Yeast are used to ferment the glucose into ethanol. There are many references in the scientific literature on this topic and you should try to learn as much as possible about the subject.

The amount of ethanol produced will be proportional to the amount of glucose you can extract from the plant material, so one possibility for a project would be to work on the problem of how to extract the cellulose from the plant material. Did you have a particular plant that you are interested in? It would probably be better to choose something that is not a food for humans, for example, corn stover or grass clippings. There are many technical challenges associated with conversion of plants to biofuels and I would suggest that you design an experiment that would solve the one of these problems. This would be a better project than simply comparing ethanol production of different plants. Your other idea of exploring conversion of other sugars is a good idea, but would require a lot more background reading to identify the problem to be solved. Here is the science buddies website guide to doing a science project. This guide will help guide you through the process. At this point, you need to start thinking of a question that you can answer with a controlled experiment.

https://www.sciencebuddies.org/science- ... ndex.shtml

Let us know if you have any questions.


Donna Hardy

Hello
Thank you for your response I have a few more questions

Will the sulfuric acid both break down the lignin and hydrolyze the cellulose to glucose? and also, How do I know how much sulfuric acid I will need? Is there a proportion that correlates to the acid and the biomass? How much sodium hydroxide will I need to use? Will I need to dilute these chemicals? If so, how many parts?

The ion exchange resin seems pretty expensive. Will I need to use a lot of it? How much yeast do you think would be needed? and How would I measure the amount of ethanol produced?

Thank you so much!

Hi. I am in year 10 this year and came up with a project idea similar to yours. I know this post is from a few years ago and you have probably done the project a while ago but I was wondering if you could help me.
I am trying to make ethanol using corn, bamboo, sugar cane and seaweed but I could not find a proper method and procedure anywhere.
What I would like to know is how you produced the ethanol ( did you use the process of fermenting) and if you measured the ethanol content afterwards did you use a vinometer?

Thankyou,
Marni